Ultra-processed food may be linked to poorer mental, physical health: Study

Researchers from Australia's Deakin University have discovered that indulging in ultra-processed food likely increases the risk of depression.

Alexandria Ee and Mahima Srinidhi Hari

Alexandria Ee and Mahima Srinidhi Hari

The Straits Times


To help manage UPF consumption, Singaporeans need to gradually replace such food with healthier alternatives. PHOTO: ST FILE

July 3, 2023

SINGAPORE – Heavy consumption of soft drinks, packaged snacks, canned meat and mass-produced bread could increase the risk of depression, according to a new study.

Researchers from Deakin University’s Food and Mood Centre in Australia have discovered that indulging in ultra-processed food (UPF) likely increases the risk of depression, particularly among people whose daily diet comprises more than 30 per cent of UPF.

The January study of 23,299 patients in Melbourne found that those with a higher dependence on UPF suffered increased odds of elevated psychological distress and are at an increased risk of mental illness – by as much as 23 per cent.

The peer-reviewed research paper, published in the Journal Of Affective Disorders in May, said poor diversity of gut microbiota – a system of micro-organisms in a person’s intestines which helps digestion and immunity – and a diet high in sugar were contributing factors.

Promises Healthcare nutritionist and therapist Teo Kiok Seng agreed with the findings, saying that excessive consumption of UPF often leads to chronic low-grade inflammation.

“Chronic low-grade inflammation damages healthy cells, tissues and organs in the body, which increases the risk of chronic diseases and depression,” she said, adding that when “our mood is affected as a result of blood sugar fluctuations, we become easily nervous or angry”.

It is difficult for many to not reach for that bag of chips, stack of crackers or cup noodles when supermarkets fill aisles with these ready-to-eat items, and workplaces stack pantries the same way.

The habit of making less healthy food choices out of convenience results in weight gain and bad cardio-metabolic outcomes such as insulin resistance, Type 2 diabetes and heart disease.

A cross-sectional study of more than 2,000 respondents here by the Singapore Food Agency’s National Centre for Food Science between October and December 2020 found that gender, age, ethnic group, housing and health status contributed to differences, to varying extents, in the consumption of processed food groups, with ethnicity being the key factor in driving the variations.

Assistant Professor Ian Ang from the Saw Swee Hock School of Public Health at the National University of Singapore said there is a need for further studies to determine the true nature of the relationship between UPF and mental health.

He suggested that people with mental health issues turn to UPF because “it’s either convenient or delicious, and may bring them (instant) joy. Or it may be that people with less time or those with more stress have mental health issues”.

Research has consistently demonstrated that a high intake of UPF is associated with increased risk of chronic diseases such as diabetes, heart disease and stroke.

An experiment was conducted at the start of 2023 by scientists from King’s College London for BBC documentary Panorama on identical twins Aimee and Nancy, 24.

One twin ate only UPF, and the other ate raw or low-processed foods with the same amount of calories and macronutrients.

After two weeks, results showed that the twin who ate only UPF gained weight, had worsened blood sugar levels and an increase in blood fat levels. The other twin was slimmer and had better blood results.

General practitioner Philip Koh said that apart from diabetes, heart disease and obesity, higher consumption of UPF is associated with a greater risk of developing cancer.

“For every 10 per cent increase in ultra-processed food in a person’s diet, there is an increased incidence of 2 per cent for cancer overall, and a 19 per cent increase for ovarian cancer specifically,” he added.

Yet, the convenience of UPF can be hard to resist.

Account manager Jasmine Goh, 49, a mother of three, acknowledged that UPF such as mass-produced bread contain additives and preservatives, and are bad for her children. But her family still buys it “out of convenience”.

“But we do regulate our intake of such foods. We buy fresh alternatives from the wet market whenever possible,” she said.

Experts said that education is key to changing habits.

Dr Candy Goh, a dietitian at Parkway MediCentre, believes that it is important to teach people how to make healthier food choices and facilitate positive behaviour change.

“Government and regulatory bodies can create a supportive regulatory framework to promote healthier food environments, such as mandatory labelling requirements and stricter regulations on marketing practices,” she added.

Dr Goh said that to help manage UPF consumption, Singaporeans need to gradually replace such food with healthier alternatives.

Reading nutrition information labels and choosing products with the Nutri-Grade or Healthier Choice symbol will also help. They have lower levels of total and saturated fats, sugars and sodium.

A balanced diet includes choosing unprocessed or minimally processed foods such as whole grains, fresh fruits and vegetables, lean proteins and healthy fats, she added.

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